Method of maintaining uniform resistance in ar-lamp circuits.



Patented Sept. 30, I902. RT.

No. 7I0,068.

E. 0. LUNDIN & F. A. GILBE 81. E. W. BURDETT, Administrators of F.

W. AJPAINE METHOD OF MAINTAINING. UNIFORM RESISTANCE A. GILBERT, Decd.IN ARC LAMP CIRCUITS.

(Application filed Apr. 30, 1902.

(No ModaI.)

voct

INVENTOR S.

WILLIFIM FLF FIINE,

EVERETT W. BURDETT,

HDMRS. OF FREDERICK H. GILBERT.

WITNESSES.

' DECEFISED EMIL O; LUNDIN.

FITTY.

P! r P3 co. motaumoq WASHINGTON o c UNITED STATES PATENT OFFICE.

EMIL LUNDIN, OF BOSTON, MASSACHUSETTS, AND XVILLIAM A. PAINE AND EVERETTW. BURDETT ADMINISTRATORS OF FREDERICK A.

GILBERT, DECEASED.

METHOD OF MAINTAINING UNIFORM RESISTANCE IN ARC-LAMP CIRCUITS.

SPECIFICATION formingpart of Letters Patent No. 7 0, dated September30,1902.

Original application filed December 17, 1897, Serial No. 662,284.Divided and this application filed April 30, 1902. Serial No. 105,314(No model.)

To all whom, it may concern.-

Be it known that we, EEIL O. LUNDIN, of Boston, county of Suffolk, andFREDERICK A. GILBERT, deceased, late of Brookline, county 5 of Norfolk,State of Massachusetts, invented ro: ing is a specification.

This invention relates to a method of n1aintaining a substantiallyuniform resistance in an electric circuit which owing to some cause isliable to have its resistance capacity changed I5 or varied; and it isparticularly adapted for use in connection with the regulation ofelectric arc lamps. Normally the feed-controlling circuit has a certainresistance, and when the current is turned on the carbons will beseparated to form the arc; but after the lamp has been burning for sometime the resistance of the feed-controlling circuit will increase by therise in temperature of the lamp. Ordinarily the power of thefeed-controlling circuit will be so reduced that the carbons will not bebrought together to reduce the length of the arc until the voltage isincreased very much. To overcome this objectionable feature, the presentpractice is to make the normal resistance of the feed-controllingcircuit less than that required to attain the proper length of are, sothat the proper resistance will not be reached until the lamp has becomeheated, and prior to such time the arc is too short, resulting in a poorli ht.

In another application, Serial No. 659,391, filed November 22, 1897, bythe same inventors was disclosed'a method for maintaining 40 theresistance substantially uniform by varying the effective extent of theresistance medium inversely to and to compensate for the change in theresistance capacity per unit of such medium due to an extraneous cause,

5 such as heating, and means were provided for carrying out theinvention when applied to an electric-arc lamp by or through means theoperation of which was due to a change in temperature of the lamp. Inthe present invention the same result is effected in another manner byutilizing the change of voltage in the lamp afterit has been burning toeither weaken the magnetic effect of the series winding or to reduce theeffective resistance of the shunt-winding.

Figure 1 in elevation represents a sufficient portion of an arc-lamp tobe understood with one embodiment of the present invention appliedthereto, and Fig. 2 is a similar View of another form of apparatus forcarrying out the invention.

Referring first to Fig. 1, a suitable metal body is provided with a baseA and top A, the upper carbon F passing through the body, top, and base,substantially as shown in the patent to the same inventors, No. 603,630,dated May 10,1898. The current enters the lamp by the line-wire L,electrically connected with the metal body, and passes thence to theupper carbon F by suitable contacts, (not shown,) then from the lowercarbon F by wire L to one of the series coils C, through the latter, andback to line at L. The series coil 0 is wound upon a suitable core atthe upper portion of the lamp-body between the top A and aninsulating-plate A intermediate the top and base, the wire L beingconnected with the inner end of the coil. One or more of the layers ofthe coil-the outmost 0, as herein shownis connected at its extremitywith the line-wire L and also with a fixed contact m by a wire m Anelectromagnet M is shown as mounted on the top A its armature on beingelectrically connected by wire or with the beginning of the layer orwinding 0, said armature being normally held bya suitable springs, asherein shown, out of contact with the terminal m, the circuit 0 m m,armature m, and wire m being thus normally open. The shunt-coil R islocated between the base A and the intermediate insulation A in shuntwith the arc, .one end of the coil being connected at 1- with thelamp-body and the other end with 'the line-wire L by wire 1' but saidshuntcoil includes the coils of the magnet M, as clearly shown. Now whenthe lamp is cold the current in the shunt-coil R will be insufficent toenergize the magnetM, and the current passing through the entire seriescoil 0 will lift the carbon F and form the arc with nearly fullseparation of the carbons. After the lamp has been burning the rise intemperature will increase the resistance of the shunt-coil; but theincrease in voltage due to burning away of the carbon is more rapid andmore current will be sent through the shunt-coil, energizing the magnetM, and the armature on will connect with the terminal 011,short-circuiting the part of the series coil 0 between the wires m mThis weakens the magnetic effect of the series coil, which is equivalentin its effect to increasing the strength of the shunt-coil, so that thecarbon will be drawn down by the action of the shunt-winding to itsproper position, shortening the arc to its proper length. After suchaction the resistance will be sufficient to properly control the feed ofthe carbon. Just as soon as the auxiliary magnet M is energized stillmore current will be forced through the shunt-winding, and the armaturewill be the more firmly held upon the contact-terminal m. In thisconstruction it is true that the resistance of the shunt-windingincreases, due to heating of the lamp, and the voltage increases morerapidly; yet the actual efiectiveness of the shuntwinding to pull thecarbon down and main tain the proper length of arc would be too slightafter the lamp has been running were it not for the cutting out orshort-circuiting of a portion of the series winding to compensate forthis decrease in the effectiveness of the shunt-winding. The increase involtage is thus made effective to maintain uniformity in the length ofthe arc notwithstanding a variation in resistance of thefeed-controlling circuit.

In Fig. 2 the device operates to maintain a substantially uniform arc;but it is accomplished in a different manner. As in Fig. 1, the seriescoil C is wound on a core'between the top A of the lamp-bodyand theintermediate insulation, the line-wire L being electrically connectedwith the body, while the current passes from lower carbon F by wire L toone end of the series winding 0, the other end of the latter beingconnected with the line at L. The shunt-coil is wound between the baseand the partition A and while practically a single coil it may be madein two parts R R, the former of copper wire and the latter ofGerman-silver wire, the part R being cut out or sl1ort-circuited, aswill be described, after the lamp has been burning for some time. A11auxiliary electromagnet M is shown mounted on the top in circuit withthe part R of the shunt-winding, the said winding being connected at 1'with the line-wire L and at r with the lamp-body. The adjacent ends ofthe two parts R R of the shunt-winding are connected by a wire r with afixed contact-terminal m the armature m of the magnet M being normallyheld away from the contact by a spring 8, said armature beingelectrically connected by a wire r with the lamp-body.

The total resistance of the shunt-winding when the lamp is cool is aboutwhat it should be for substantially the proper length of arc in startingthe lamp; but insufficient current will pass through the shunt-windingto energize the magnet H and operate its armature. After the lamp hasbeen burning for a time, however, the carbon will have burned away,increasing the length of the arc, and the voltage at the arc willincrease, sending more current through the shunt-winding. This increasein the voltage is more rapid than the increased resistance of theshunt-winding due to heating of the lamp, and at a certain point thecurrent passing will be sufficient to energize the magnet M, closing theauxiliary circuit at m and thereby cutting out the portion R of theshunt-wind ing, such portion cut out being calculated so that theimmediately-following increase of currentin the remaining portion of theshuntwinding will have sufficient power to draw the carbon down andreduce the arc to the proper length. Thus in each case the length of thearc is controlled by or through the increase of voltage, and in bothcases the device is regulated as to the time of its operation by meansof the spring controlling the armature of the auxiliary 1nagnet,'so thatas the spring is made stronger or weaker the increase of voltage will becorrespondingly greater or less before the change in one or the other ofthe coils is effected.

In the construction shown in Fig. 1 the effectiveness of the serieswinding is reduced by reducing the efiective extent of the coilwhile inthe construction shown in Fig. 2 the same final result is attained, butby decreasing the resistance of the shunt winding through a reduction inthe effective extent of the resistance medium.

The present case is a division of the application of the same inventors,Serial No. 662,284, filed December 17, 1897.

What is claimed as new is 1. The method of regulating electric-arc lampshaving series and shunt regulatingcoils, which consists in varying theregulating power of said coils when the heat after starting the lamp,inversely to, and to compensate for, change of voltage at the arcaccompanying such heating.

2. The method of regulating arc-lamps having series and shuntarc-regulating coils, which consists in automatically cutting out a partof one of said coils when it heats after starting the lamp, tocompensate for the change of voltage at the arc accompanying suchheating.

3. The method of regulating electric-arc lamps having series and shuntregulatingcoils, which consists in increasing the power of theshunt-coil when it heats after starting the lamp, to compensate for theincreased IIO voltage at the arc accompanying the rise of coilresistance due to such heating, whereby the shunt-winding is rendereduniform in the starting and running condition of the lamp, and thelength of arc is also maintained uniform.

4. The method of regulating electric-arc lamps and maintaining uniformarc length, which consists in automatically controlling the operation ofthe feed-regulating circuit when it heats after starting the lamp, by,and to compensate for, variation of voltage at the arc accompanying thechange of coil resistance due to such heating.

5. The method of regulating electric-arc lamps, which consists inautomatically increasing the efitective power of the feed-controllingcircuit to compensate for loss of power due to heating of the circuitwhen the voltage at the arc rises as a consequence of such heat- 20 ingto a determinate degree.

In witness whereof we have hereunto set our hands this 25th day ofMarch, 1902.

EMIL O. LUNDIN. WILLIAM A. PAINE,

EVERETT W. BURDETT, Administrators of the estate of Frederick A.

Gilbert, deceased.

Witnesses to E. O. L.:

JOHN GORDON, M. JOHNSTON.

Witnesses to W. A. P.:

R. GEO. REsTALL, JOHN GORDON.

Witnesses to E. W. 13.: JOHN GORDON, CHARLES A. SNOW.

Correction in Letters Patent No. 710,068.

It is hereby certified that in Letters Patent N 0. 710,068, grantedSeptember 30, 1902, upon the application of Emil O. Lundin, of Boston,Massachusetts, and William A.

Paine and Everett W. Burdett, administrators of Frederick A. Gilbert,deceased, for an improvement in Quits, printed specification requiringcorrection, as follows: In

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Ofiice.

Signed and sealed this 31st day of March, A. D., 1903.

[SEAL] F. I. ALLEN,

Commissioner of Patents.

Correction in Letters Patent No. 710,068.-

cuits, an error appears in the printed specification requiringcorrection, as follows: In

line 119, page 2, the word the should read they; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record I of the case in the Patent Ofiice. Q

Signed and sealed this 31st day of March, A. D., 1903.

[SEAL] F. I. ALLEN,

Commissioner of Patents.

